Fig. 1: Crystallographic structure of NBCP and fitting loss landscape.
From: Spin supersolidity in nearly ideal easy-axis triangular quantum antiferromagnet Na2BaCo(PO4)2
a Top view of the crystallographic structure of the NBCP. Each Co2+ ion carries an effective Sā=ā1/2 spin owing to the octahedral crystal environment and the spin-orbital coupling. The spins form a triangular network. Its magnetic ground state is a spin supersolid: the red (blue) circles represent the positive (negative) Sz component, and the black arrows show the direction of the Sx,y component. The crystallographic a-, b-, and c-axes and the spin frame Sx,y,z are shown in the bottom right and the top left insets, respectively. b Shows the projection of the fitting loss function onto the JxyāāāJz plane (with JPD,Ī fixed as zero), where brighter color represents less fitting loss and therefore better fit. The white cross marks the optimal parameter set, which corresponds to an Sā=ā1/2 TLAF with anisotropy parameter Īā=āJz/Jxyāāā1.7 (dashed line).
